Application of nanotechnology in the agri-food sector is one of the fastest growing fields in nano-research. Innovating and generating technology to produce the quantity and quality of food, sufficient to feed a rapidly growing world population, will always be the biggest challenge in modern times. The excessive and indiscriminate use of synthetic agrochemicals to increase the yield of agricultural crops leads to the deterioration of soil health, to the degradation of agroecosystems, triggering problems related to environmental pollution and creating resistance to pesticides by many insects and microorganisms. In this context, nanotechnology has emerged as a scientific advance that can transform agricultural sectors, providing tools for the rapid detection of pests and diseases in crops, as well as improving the ability of plants to absorb nutrients, to grow faster and to generate better yields. Nanotechnology opens a wide range of opportunities in agriculture to produce agroproducts such as nano-fertilizers, nano-pesticides, nano-herbicides, and nano-sensors which will allow to increase the yield of food in a sustainable way by reducing the environmental impact. It is expected that this critical review provides the background information on agro-nano technological research, which will allow us to advance with the experimentation on the applications of nanoparticles in ecological farming.